Flipping the boat

Today's plan is to get the boat upside down.  The boat weighs about 900 pounds.  One-third of this weight is the 300 pound keel.  The boat is currently sitting on its side with the keel sitting on some blocks. 

I'll try to explain what I tried.  My first attempt was to get straps around the boat at the front and back.  One side of the straps much shorter than the other side.  The idea was to pull on the shorter side with the chain hoists which would cause the boat to roll.  This started to work until the keel was off the blocks.  The keel was doing its job trying to keep the boat upright.  The boat started to slowly slip in the straps remaining upright no matter how much I tried to lift it. 

I felt both good and bad about this at the same time.  I felt good because it gives me further confidence that this boat will be difficult to capsize once in the water.  Bad because I had to figure a new way to get it upside down.

I decided to grab the keel with one of the straps.  I wasn't sure how good this would work because I had no way to support one side of the boat.  I only had 2 gantries.  One on the front and one on the keel.  It worked surprisingly well.  The boat slowly rolled upside down.   I then set it back down on the ground so I could move the gantry and get under it properly to raise it off the ground again. 

How am I going to roll it back upside right?  I'm not quite sure yet.  =)   I'll figure that out when I get to it.